Diabetics Are at Increased Risk of Developing Alzheimer’s and Other Dementia

Adults with diabetes are more likely to experience dementia than those with normal glucose tolerance, recent results from a longitudinal study conducted in Japan have shown.

The research team was headed by Yutaka Kiyohara, M.D., Ph.D., KyushuUniversity, Fukuoka, Japan. The team analyzed a sample group of 1,017 community-dwelling older diabetics; the findings of the study were published in the journal Neurology.

The study found that patients who had been diagnosed with diabetes had a 74% greater chance of developing dementia 15 years after the initiation of the study. None of the study participants had dementia when the investigation began, and they all took an oral glucose test at age 60 or older. Researchers followed up with the patients 15 years after the study was initiated to determine whether any of them had developed dementia, such as Alzheimer’s disease.

Patients who had been living with diabetes were 2.05 times more likely to have developed Alzheimer’s than individuals with normal glucose tolerance; the researchers adjusted for confounding factors, including age and gender.

Richard Bergenstal, M.D., of the InternationalDiabetesCenter at Park Nicollet, Minneapolis, Minn., commented that the study’s results were interesting in that post-load glucose levels were a statistically significant predictor of dementia status. Study participants who showed high blood-glucose levels two hours after eating a meal were more likely to develop dementia later in life.

Patients who displayed a postload glucose level of 7.8 to 11.0 mmol/L were 50% more likely to develop all-cause dementia, while those with a postload glucose level of above 11.0 mmol/L were 2.47 times more likely to develop all-cause dementia and 3.42 times more likely to develop Alzheimer's. Post-meal glucose levels therefore seemed to have a significant impact on risk of developing dementia and especially on the risk of Alzheimer’s.

The research group commented that “postprandial glucose regulation is critical to prevent future dementia.

“Our findings emphasize the need to consider diabetes as a potential risk factor for all-cause dementia, Alzheimer’s disease, and probably vascular dementia,” the group added.

Bergenstal, who previously served as president of the American Diabetes Association, cautioned that the mechanisms behind high postload glucose levels and increased risk of dementia were not yet fully understood, and further studies would need to be conducted before the findings could be incorporated into treatment of diabetics. “We need to understand it a lot better before we build this into our clinical practice. We don’t know yet from these studies how to intervene,” Bergenstal said.